This invention relates generally to power distribution blocks or terminal blocks and, more particularly, to power distribution blocks for vehicle electrical systems.
Fuses are widely used as overcurrent protection devices to prevent costly damage to electrical circuits. Fuse terminals typically form an electrical connection between an electrical power source and an electrical component or a combination of components arranged in an electrical circuit. One or more fusible links or elements, or a fuse element assembly, is connected between the fuse terminals, so that when electrical current through the fuse exceeds a predetermined limit, the fusible elements melt and opens one or more circuits through the fuse to prevent electrical component damage
Power distribution blocks and terminal blocks are sometimes utilized to collect a plurality of fuses in a central location in an electrical system. Conventionally, fuse blocks include individually wired circuits within the block for power input. As such, when it is desired to power more than one circuit with the same power source, a jumper is installed for this purpose. Installation of jumpers, however, is costly, labor intensive, and time consuming. In addition, added circuits require the use of larger gauge wiring in order to handle the additional current load. Accommodation of additional loads and auxiliary circuits with conventional fuse blocks used in, for example, vehicle electrical systems, is therefore difficult. Electrical systems of many vehicles now include expanded electrical systems to accommodate additional vehicle features and entertainment devices. Some types of vehicles, for example, watercraft, buses, and recreational vehicles include separately powered auxiliary loads for such purposes, and wiring these loads to auxiliary power sources adds to the complexity and difficulty of wiring the electrical system of the vehicle.
At least some existing fuse blocks are configured for plug-in connection to circuitry to avoid labor intensive hard-wired connections. See for example, U.S. Pat. No. 6,431,880. Connections in such fuse blocks are made to one or more internal buses to selectively distribute electrical power to, for example, different electrical subsystems of a vehicle. The use of a second internal bus allows a user to switch a bank of relays at the same time. This type of switching can be used accomplished using either power or ground. Such fuse blocks, however, are commonly used with switching elements which must be separately wired from the fuse block so that power can be selectively switched to certain components or circuits in the electrical system. Additionally, switching elements permit convenient disconnection of associated circuits from the power source during maintenance procedures, and avoids a need to remove and reinstall fuses in vehicle environments where access to the fuses is often restrictive.
Power distribution blocks are known which may accommodate fuse, circuit breakers, and relay switches in a single package, and thus provide both overcurrent protection and convenient switching of power in a single package. One such power distribution block, sometimes referred to as a vehicle electrical center (VEC) is commercially available from Cooper/Bussmann of St. Louis, Mo. However, these power distribution blocks tend to be too large and/or too expensive for use in certain applications, and also contain features that are not necessary for many applications. For example, some specialty vehicles, construction and agricultural equipment, marine applications, and truck, bus, and RV applications do not require the sophistication of the VEC or justify the cost of such distribution blocks.
Additionally, specialty vehicles, construction and agricultural equipment, marine applications, and truck, bus, and RV applications often entail additional moisture, vibration, and contaminant issues in use which are not experienced by conventional fuse blocks or power distribution blocks for automotive applications. Thus, conventional fuse blocks and power distribution are poorly suited for certain applications.